Transvaginal cervical length scans to prevent prematurity in twins

A randomized controlled trial Presented in abstract form at the 27th Annual Clinic Meeting of the Society for Maternal-Fetal Medicine, San Francisco, CA, Feb 5-10, 2007.

Michael C. Gordon, David S. McKenna, Theresa L. Stewart, Bobby Howard, Kimberly F. Foster, Kenneth Higby, Rebecca L. Cypher, William H. Barth

Research output: Contribution to journalArticle

13 Citations (Scopus)

Abstract

Background Twin pregnancies are associated with an increased risk of perinatal morbidity and mortality primarily due to spontaneous preterm deliveries. The mean gestational age for delivery is 35.3 weeks and twins account for 23% of preterm births <32 weeks. A number of strategies have been proposed to prevent preterm deliveries: tocolytics, bed rest, hospitalization, home uterine activity monitoring, cerclage, and most recently, progesterone. Unfortunately, none have proven effective. Recent metaanalyses and reviews suggest that transvaginal cervical length (TVCL) ultrasound in the second trimester is a powerful predictor of preterm birth among asymptomatic women. Indeed, TVCL has the highest positive and negative predictive values for determining the risk of spontaneous preterm delivery in twin pregnancies. It follows that TVCL assessment may allow identification of a subset of twin pregnancies that re better candidates for interventions intended to prevent prematurity. Objective We sought to determine whether use of TVCL prolongs gestation in twin pregnancies. Study Design This is a multicenter, randomized, controlled trial of 125 dichorionic or monochorionic/diamniotic twin pregnancies without prior preterm birth <28 weeks. The study group (n = 63) had TVCL and digital exams monthly from 16-28 weeks and were managed with a standard algorithm for activity restriction and cerclage. The control group (n = 62) had monthly digital cervical examinations but no routine TVCL ultrasound examinations. The primary outcome was gestational age at delivery. Secondary outcomes included percentage of deliveries <35 weeks, and maternal and neonatal outcomes. Results The mean gestational age at delivery was 35.7 weeks (95% confidence interval [CI], 35.2-36.2) among those managed with TVCL and 35.5 weeks (95% CI, 34.7-36.4) among the control patients. The Kaplan-Meier estimates of deliveries <38 weeks were not significantly different between groups. This was true whether we compared curves with a log-rank test (P =.67), Breslow test (P =.67), or Tarone-Ware test (P =.64). The percentage of deliveries <35 0/7 weeks did not differ: 27.4% for subjects managed with routine TVCL and 28.6% for control subjects (relative risk, 0.96; 95% CI, 0.60-1.54). Our study had an 80% power to detect a 12-day difference in the gestational age at delivery with 95% confidence. Conclusion The overall mean length of gestation and the percentage of women delivering <35 weeks did not differ between twin gestations managed with TVCL and digital exams monthly from 16-28 weeks with a standard algorithm for activity restriction and cerclage and controls who had monthly digital cervical examinations but no routine TVCL. Routine second-trimester transvaginal ultrasound assessment of cervical length is not associated with improved outcomes when incorporated into the standard management of otherwise low-risk twin pregnancies.

Original languageEnglish (US)
Pages (from-to)277.e1-277.e7
JournalAmerican Journal of Obstetrics and Gynecology
Volume214
Issue number2
DOIs
StatePublished - Feb 1 2016

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Twin Pregnancy
San Francisco
Randomized Controlled Trials
Gestational Age
Premature Birth
Second Pregnancy Trimester
Confidence Intervals
Pregnancy
Uterine Monitoring
Tocolytic Agents
Bed Rest
Perinatal Mortality
Kaplan-Meier Estimate
Progesterone
Hospitalization
Mothers
Morbidity
Control Groups

All Science Journal Classification (ASJC) codes

  • Obstetrics and Gynecology

Cite this

Transvaginal cervical length scans to prevent prematurity in twins : A randomized controlled trial Presented in abstract form at the 27th Annual Clinic Meeting of the Society for Maternal-Fetal Medicine, San Francisco, CA, Feb 5-10, 2007. / Gordon, Michael C.; McKenna, David S.; Stewart, Theresa L.; Howard, Bobby; Foster, Kimberly F.; Higby, Kenneth; Cypher, Rebecca L.; Barth, William H.

In: American Journal of Obstetrics and Gynecology, Vol. 214, No. 2, 01.02.2016, p. 277.e1-277.e7.

Research output: Contribution to journalArticle

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title = "Transvaginal cervical length scans to prevent prematurity in twins: A randomized controlled trial Presented in abstract form at the 27th Annual Clinic Meeting of the Society for Maternal-Fetal Medicine, San Francisco, CA, Feb 5-10, 2007.",
abstract = "Background Twin pregnancies are associated with an increased risk of perinatal morbidity and mortality primarily due to spontaneous preterm deliveries. The mean gestational age for delivery is 35.3 weeks and twins account for 23{\%} of preterm births <32 weeks. A number of strategies have been proposed to prevent preterm deliveries: tocolytics, bed rest, hospitalization, home uterine activity monitoring, cerclage, and most recently, progesterone. Unfortunately, none have proven effective. Recent metaanalyses and reviews suggest that transvaginal cervical length (TVCL) ultrasound in the second trimester is a powerful predictor of preterm birth among asymptomatic women. Indeed, TVCL has the highest positive and negative predictive values for determining the risk of spontaneous preterm delivery in twin pregnancies. It follows that TVCL assessment may allow identification of a subset of twin pregnancies that re better candidates for interventions intended to prevent prematurity. Objective We sought to determine whether use of TVCL prolongs gestation in twin pregnancies. Study Design This is a multicenter, randomized, controlled trial of 125 dichorionic or monochorionic/diamniotic twin pregnancies without prior preterm birth <28 weeks. The study group (n = 63) had TVCL and digital exams monthly from 16-28 weeks and were managed with a standard algorithm for activity restriction and cerclage. The control group (n = 62) had monthly digital cervical examinations but no routine TVCL ultrasound examinations. The primary outcome was gestational age at delivery. Secondary outcomes included percentage of deliveries <35 weeks, and maternal and neonatal outcomes. Results The mean gestational age at delivery was 35.7 weeks (95{\%} confidence interval [CI], 35.2-36.2) among those managed with TVCL and 35.5 weeks (95{\%} CI, 34.7-36.4) among the control patients. The Kaplan-Meier estimates of deliveries <38 weeks were not significantly different between groups. This was true whether we compared curves with a log-rank test (P =.67), Breslow test (P =.67), or Tarone-Ware test (P =.64). The percentage of deliveries <35 0/7 weeks did not differ: 27.4{\%} for subjects managed with routine TVCL and 28.6{\%} for control subjects (relative risk, 0.96; 95{\%} CI, 0.60-1.54). Our study had an 80{\%} power to detect a 12-day difference in the gestational age at delivery with 95{\%} confidence. Conclusion The overall mean length of gestation and the percentage of women delivering <35 weeks did not differ between twin gestations managed with TVCL and digital exams monthly from 16-28 weeks with a standard algorithm for activity restriction and cerclage and controls who had monthly digital cervical examinations but no routine TVCL. Routine second-trimester transvaginal ultrasound assessment of cervical length is not associated with improved outcomes when incorporated into the standard management of otherwise low-risk twin pregnancies.",
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T1 - Transvaginal cervical length scans to prevent prematurity in twins

T2 - A randomized controlled trial Presented in abstract form at the 27th Annual Clinic Meeting of the Society for Maternal-Fetal Medicine, San Francisco, CA, Feb 5-10, 2007.

AU - Gordon, Michael C.

AU - McKenna, David S.

AU - Stewart, Theresa L.

AU - Howard, Bobby

AU - Foster, Kimberly F.

AU - Higby, Kenneth

AU - Cypher, Rebecca L.

AU - Barth, William H.

PY - 2016/2/1

Y1 - 2016/2/1

N2 - Background Twin pregnancies are associated with an increased risk of perinatal morbidity and mortality primarily due to spontaneous preterm deliveries. The mean gestational age for delivery is 35.3 weeks and twins account for 23% of preterm births <32 weeks. A number of strategies have been proposed to prevent preterm deliveries: tocolytics, bed rest, hospitalization, home uterine activity monitoring, cerclage, and most recently, progesterone. Unfortunately, none have proven effective. Recent metaanalyses and reviews suggest that transvaginal cervical length (TVCL) ultrasound in the second trimester is a powerful predictor of preterm birth among asymptomatic women. Indeed, TVCL has the highest positive and negative predictive values for determining the risk of spontaneous preterm delivery in twin pregnancies. It follows that TVCL assessment may allow identification of a subset of twin pregnancies that re better candidates for interventions intended to prevent prematurity. Objective We sought to determine whether use of TVCL prolongs gestation in twin pregnancies. Study Design This is a multicenter, randomized, controlled trial of 125 dichorionic or monochorionic/diamniotic twin pregnancies without prior preterm birth <28 weeks. The study group (n = 63) had TVCL and digital exams monthly from 16-28 weeks and were managed with a standard algorithm for activity restriction and cerclage. The control group (n = 62) had monthly digital cervical examinations but no routine TVCL ultrasound examinations. The primary outcome was gestational age at delivery. Secondary outcomes included percentage of deliveries <35 weeks, and maternal and neonatal outcomes. Results The mean gestational age at delivery was 35.7 weeks (95% confidence interval [CI], 35.2-36.2) among those managed with TVCL and 35.5 weeks (95% CI, 34.7-36.4) among the control patients. The Kaplan-Meier estimates of deliveries <38 weeks were not significantly different between groups. This was true whether we compared curves with a log-rank test (P =.67), Breslow test (P =.67), or Tarone-Ware test (P =.64). The percentage of deliveries <35 0/7 weeks did not differ: 27.4% for subjects managed with routine TVCL and 28.6% for control subjects (relative risk, 0.96; 95% CI, 0.60-1.54). Our study had an 80% power to detect a 12-day difference in the gestational age at delivery with 95% confidence. Conclusion The overall mean length of gestation and the percentage of women delivering <35 weeks did not differ between twin gestations managed with TVCL and digital exams monthly from 16-28 weeks with a standard algorithm for activity restriction and cerclage and controls who had monthly digital cervical examinations but no routine TVCL. Routine second-trimester transvaginal ultrasound assessment of cervical length is not associated with improved outcomes when incorporated into the standard management of otherwise low-risk twin pregnancies.

AB - Background Twin pregnancies are associated with an increased risk of perinatal morbidity and mortality primarily due to spontaneous preterm deliveries. The mean gestational age for delivery is 35.3 weeks and twins account for 23% of preterm births <32 weeks. A number of strategies have been proposed to prevent preterm deliveries: tocolytics, bed rest, hospitalization, home uterine activity monitoring, cerclage, and most recently, progesterone. Unfortunately, none have proven effective. Recent metaanalyses and reviews suggest that transvaginal cervical length (TVCL) ultrasound in the second trimester is a powerful predictor of preterm birth among asymptomatic women. Indeed, TVCL has the highest positive and negative predictive values for determining the risk of spontaneous preterm delivery in twin pregnancies. It follows that TVCL assessment may allow identification of a subset of twin pregnancies that re better candidates for interventions intended to prevent prematurity. Objective We sought to determine whether use of TVCL prolongs gestation in twin pregnancies. Study Design This is a multicenter, randomized, controlled trial of 125 dichorionic or monochorionic/diamniotic twin pregnancies without prior preterm birth <28 weeks. The study group (n = 63) had TVCL and digital exams monthly from 16-28 weeks and were managed with a standard algorithm for activity restriction and cerclage. The control group (n = 62) had monthly digital cervical examinations but no routine TVCL ultrasound examinations. The primary outcome was gestational age at delivery. Secondary outcomes included percentage of deliveries <35 weeks, and maternal and neonatal outcomes. Results The mean gestational age at delivery was 35.7 weeks (95% confidence interval [CI], 35.2-36.2) among those managed with TVCL and 35.5 weeks (95% CI, 34.7-36.4) among the control patients. The Kaplan-Meier estimates of deliveries <38 weeks were not significantly different between groups. This was true whether we compared curves with a log-rank test (P =.67), Breslow test (P =.67), or Tarone-Ware test (P =.64). The percentage of deliveries <35 0/7 weeks did not differ: 27.4% for subjects managed with routine TVCL and 28.6% for control subjects (relative risk, 0.96; 95% CI, 0.60-1.54). Our study had an 80% power to detect a 12-day difference in the gestational age at delivery with 95% confidence. Conclusion The overall mean length of gestation and the percentage of women delivering <35 weeks did not differ between twin gestations managed with TVCL and digital exams monthly from 16-28 weeks with a standard algorithm for activity restriction and cerclage and controls who had monthly digital cervical examinations but no routine TVCL. Routine second-trimester transvaginal ultrasound assessment of cervical length is not associated with improved outcomes when incorporated into the standard management of otherwise low-risk twin pregnancies.

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